[llvm] 8f3f93c - [SampleFDO] Match functions with the same base function name (#126688)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 24 10:11:59 PDT 2025
Author: Lei Wang
Date: 2025-03-24T10:11:55-07:00
New Revision: 8f3f93cd78cfbf1dea349be2eef98802da8ad929
URL: https://github.com/llvm/llvm-project/commit/8f3f93cd78cfbf1dea349be2eef98802da8ad929
DIFF: https://github.com/llvm/llvm-project/commit/8f3f93cd78cfbf1dea349be2eef98802da8ad929.diff
LOG: [SampleFDO] Match functions with the same base function name (#126688)
Sometimes, there may be no matched anchors but the functions still
match. e.g. if the function’s template typename changes, all the
callsites that use the type are mismatched and the caller function that
contains those callsite are mismatched. Introduce a check to match the
functions if their demangled base names are the same.
Added:
llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof
llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll
Modified:
llvm/lib/Transforms/IPO/CMakeLists.txt
llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/CMakeLists.txt b/llvm/lib/Transforms/IPO/CMakeLists.txt
index eb048fa814dd1..1c4ee0336d4db 100644
--- a/llvm/lib/Transforms/IPO/CMakeLists.txt
+++ b/llvm/lib/Transforms/IPO/CMakeLists.txt
@@ -65,6 +65,7 @@ add_llvm_component_library(LLVMipo
FrontendOpenMP
InstCombine
IRReader
+ Demangle
Linker
Object
ProfileData
diff --git a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
index 98fab6ac3f4b9..d6d1b7c51d4c0 100644
--- a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/SampleProfileMatcher.h"
+#include "llvm/Demangle/Demangle.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/CommandLine.h"
@@ -727,6 +728,33 @@ bool SampleProfileMatcher::functionMatchesProfileHelper(
// two sequences are.
float Similarity = 0.0;
+ // Match the functions if they have the same base name(after demangling) and
+ // skip the similarity check.
+ ItaniumPartialDemangler Demangler;
+ // Helper lambda to demangle and get the base name. If the demangling failed,
+ // return an empty string.
+ auto GetBaseName = [&](StringRef FName) {
+ auto FunctionName = FName.str();
+ if (Demangler.partialDemangle(FunctionName.c_str()))
+ return std::string();
+ constexpr size_t MaxBaseNameSize = 4096;
+ char BaseNameBuf[MaxBaseNameSize] = {};
+ size_t BaseNameSize = MaxBaseNameSize;
+ char *BaseNamePtr =
+ Demangler.getFunctionBaseName(BaseNameBuf, &BaseNameSize);
+ return (BaseNamePtr && BaseNameSize)
+ ? std::string(BaseNamePtr, BaseNameSize)
+ : std::string();
+ };
+ auto IRBaseName = GetBaseName(IRFunc.getName());
+ auto ProfBaseName = GetBaseName(ProfFunc.stringRef());
+ if (!IRBaseName.empty() && IRBaseName == ProfBaseName) {
+ LLVM_DEBUG(dbgs() << "The functions " << IRFunc.getName() << "(IR) and "
+ << ProfFunc << "(Profile) share the same base name: "
+ << IRBaseName << ".\n");
+ return true;
+ }
+
const auto *FSForMatching = getFlattenedSamplesFor(ProfFunc);
// With extbinary profile format, initial profile loading only reads profile
// based on current function names in the module.
diff --git a/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof b/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof
new file mode 100644
index 0000000000000..e194d4d4aae32
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof
@@ -0,0 +1,12 @@
+main:200:0
+ 1: 0
+ 2: 50
+ 3: 0
+ 4: 50
+ 5: 52 _Z3fooi:52
+ 6: 50
+ 7: 0
+ !CFGChecksum: 281582264815352
+_Z3fooi:52:52
+ 1: 52
+ !CFGChecksum: 4294967295000
diff --git a/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll b/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll
new file mode 100644
index 0000000000000..4e435f4586465
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll
@@ -0,0 +1,133 @@
+; REQUIRES: x86_64-linux
+; REQUIRES: asserts
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-stale-profile-name-similarity.prof --salvage-stale-profile --salvage-unused-profile -S --debug-only=sample-profile,sample-profile-matcher,sample-profile-impl 2>&1 | FileCheck %s
+
+; CHECK: Function _Z3fool is not in profile or profile symbol list.
+; CHECK: Run stale profile matching for main
+; CHECK: The functions _Z3fool(IR) and _Z3fooi(Profile) share the same base name: foo
+; CHECK: Function:_Z3fool matches profile:_Z3fooi
+; CHECK: Run stale profile matching for _Z3fool
+
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at x = dso_local global i32 0, align 4, !dbg !0
+
+; Function Attrs: mustprogress noinline nounwind uwtable
+define dso_local void @_Z3fool(i64 noundef %y) #0 !dbg !17 {
+entry:
+ #dbg_value(i64 %y, !22, !DIExpression(), !23)
+ call void @llvm.pseudoprobe(i64 5326982120444056491, i64 1, i32 0, i64 -1), !dbg !24
+ %0 = load volatile i32, ptr @x, align 4, !dbg !25, !tbaa !26
+ %conv = sext i32 %0 to i64, !dbg !25
+ %add = add nsw i64 %conv, %y, !dbg !25
+ %conv1 = trunc i64 %add to i32, !dbg !25
+ store volatile i32 %conv1, ptr @x, align 4, !dbg !25, !tbaa !26
+ ret void, !dbg !30
+}
+
+; Function Attrs: mustprogress norecurse nounwind uwtable
+define dso_local noundef i32 @main() #1 !dbg !31 {
+entry:
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 1, i32 0, i64 -1), !dbg !37
+ #dbg_value(i32 0, !35, !DIExpression(), !38)
+ br label %for.cond, !dbg !39
+
+for.cond: ; preds = %for.body, %entry
+ %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ], !dbg !40
+ #dbg_value(i32 %i.0, !35, !DIExpression(), !38)
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 2, i32 0, i64 -1), !dbg !41
+ %cmp = icmp slt i32 %i.0, 1000000, !dbg !43
+ br i1 %cmp, label %for.body, label %for.cond.cleanup, !dbg !44
+
+for.cond.cleanup: ; preds = %for.cond
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 3, i32 0, i64 -1), !dbg !45
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 7, i32 0, i64 -1), !dbg !46
+ ret i32 0, !dbg !46
+
+for.body: ; preds = %for.cond
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 4, i32 0, i64 -1), !dbg !47
+ %conv = sext i32 %i.0 to i64, !dbg !47
+ call void @_Z3fool(i64 noundef %conv), !dbg !49
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 6, i32 0, i64 -1), !dbg !51
+ %inc = add nsw i32 %i.0, 1, !dbg !51
+ #dbg_value(i32 %inc, !35, !DIExpression(), !38)
+ br label %for.cond, !dbg !52, !llvm.loop !53
+}
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare void @llvm.lifetime.start.p0(i64 immarg, ptr captures(none)) #2
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare void @llvm.lifetime.end.p0(i64 immarg, ptr captures(none)) #2
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite)
+declare void @llvm.pseudoprobe(i64, i64, i32, i64) #3
+
+attributes #0 = { mustprogress noinline nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "use-sample-profile" }
+attributes #1 = { mustprogress norecurse nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "use-sample-profile" }
+attributes #2 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+attributes #3 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!7, !8, !9, !10, !11, !12, !13}
+!llvm.ident = !{!14}
+!llvm.pseudo_probe_desc = !{!15, !16}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 21.0.0git (https://github.com/llvm/llvm-project.git c9f1d2cbf18990311ea1287cc154e3784a10a3b0)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "test_rename.c", directory: "/home", checksumkind: CSK_MD5, checksum: "2991f6c78cef4c393285c97c0f5dabc4")
+!4 = !{!0}
+!5 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !6)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !{i32 7, !"Dwarf Version", i32 5}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"wchar_size", i32 4}
+!10 = !{i32 8, !"PIC Level", i32 2}
+!11 = !{i32 7, !"PIE Level", i32 2}
+!12 = !{i32 7, !"uwtable", i32 2}
+!13 = !{i32 7, !"debug-info-assignment-tracking", i1 true}
+!14 = !{!"clang version 21.0.0git (https://github.com/llvm/llvm-project.git c9f1d2cbf18990311ea1287cc154e3784a10a3b0)"}
+!15 = !{i64 5326982120444056491, i64 4294967295, !"_Z3fool"}
+!16 = !{i64 -2624081020897602054, i64 281582264815352, !"main"}
+!17 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fool", scope: !3, file: !3, line: 3, type: !18, scopeLine: 3, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !21)
+!18 = !DISubroutineType(types: !19)
+!19 = !{null, !20}
+!20 = !DIBasicType(name: "long", size: 64, encoding: DW_ATE_signed)
+!21 = !{!22}
+!22 = !DILocalVariable(name: "y", arg: 1, scope: !17, file: !3, line: 3, type: !20)
+!23 = !DILocation(line: 0, scope: !17)
+!24 = !DILocation(line: 4, column: 9, scope: !17)
+!25 = !DILocation(line: 4, column: 6, scope: !17)
+!26 = !{!27, !27, i64 0}
+!27 = !{!"int", !28, i64 0}
+!28 = !{!"omnipotent char", !29, i64 0}
+!29 = !{!"Simple C++ TBAA"}
+!30 = !DILocation(line: 5, column: 1, scope: !17)
+!31 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 7, type: !32, scopeLine: 7, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !34)
+!32 = !DISubroutineType(types: !33)
+!33 = !{!6}
+!34 = !{!35}
+!35 = !DILocalVariable(name: "i", scope: !36, file: !3, line: 8, type: !6)
+!36 = distinct !DILexicalBlock(scope: !31, file: !3, line: 8, column: 3)
+!37 = !DILocation(line: 8, column: 12, scope: !36)
+!38 = !DILocation(line: 0, scope: !36)
+!39 = !DILocation(line: 8, column: 8, scope: !36)
+!40 = !DILocation(line: 8, scope: !36)
+!41 = !DILocation(line: 8, column: 19, scope: !42)
+!42 = distinct !DILexicalBlock(scope: !36, file: !3, line: 8, column: 3)
+!43 = !DILocation(line: 8, column: 21, scope: !42)
+!44 = !DILocation(line: 8, column: 3, scope: !36)
+!45 = !DILocation(line: 0, scope: !31)
+!46 = !DILocation(line: 11, column: 1, scope: !31)
+!47 = !DILocation(line: 9, column: 11, scope: !48)
+!48 = distinct !DILexicalBlock(scope: !42, file: !3, line: 8, column: 41)
+!49 = !DILocation(line: 9, column: 7, scope: !50)
+!50 = !DILexicalBlockFile(scope: !48, file: !3, discriminator: 455082031)
+!51 = !DILocation(line: 8, column: 37, scope: !42)
+!52 = !DILocation(line: 8, column: 3, scope: !42)
+!53 = distinct !{!53, !44, !54, !55}
+!54 = !DILocation(line: 10, column: 3, scope: !36)
+!55 = !{!"llvm.loop.mustprogress"}
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